Coral Cardinalfish – Pregnancy Siphamia corallicola

It’s a well known fact the male seahorses incubate their fertilised eggs. It is also fairly well known that male Jawfish incubate their fertilised eggs in their mouths. It is much less known that another species of fish, the Cardinalfish, do the same.

What I definitely didn’t know, until I saw this rare Coral Cardinalfish, was what late-stage pregnancy looked like!!

We occasionally see, usually Banggai, Cardinalfish with a mouth full of eggs. And it always looks like that, the mouth is slightly open and you can see the eggs hidden inside. This week I saw this rare Coral Cardinalfish and didn’t really know what to make of it, as the eggs were definitely not ‘inside’, but were bulging out.

At first I thought that the Cardinalfish had found a clutch of something else’s eggs and was having a banquet. But when I got back to the resort I started to investigate and found that a couple of days before finally hatching the incubating egg masses start to engorge and spill out of the brooding male’s mouth. It is very rare to see them in this state, which was confirmed when I showed the guides the video and they had never seen it before.